Ligand Exchange Treatments in PbS Quantum Dot Solar Cells

Back in the summer of 2017, I participated in research in a physics lab for the first time. That summer I worked with Professor Alexi Arango in his lab at Mount Holyoke College, where we attempt to create devices that generate electricity using solar energy. The ultimate goal of the lab is to construct efficient tandem cells, which would lead to large-area, lightweight, flexible solar cells. Participating in the research in his lab was a lot of fun, and an excellent first experience in a physics lab. It was also very rewarding, since it contributes to the increasingly important task of eliminating greenhouse gas emissions.

The summer I was working there we focused on experimenting with lead-sulfide (PbS) quantum dots as an absorption layer for the devices we constructed. Quantum dots are basically very small semiconductor particles that are only several nano-meters in diameter. Lead-sulfide quantum dots are an attractive material for creating solar cells, particularly because they have a low fabrication cost. Throughout the summer, I worked with a few other students to familiarize ourselves with the process of creating PbS quantum dot solar cells, taking part in experiments on the each of the different steps in fabricating these solar cells, collecting data on absorption, open-circuit voltage, and efficiency, and understanding what the data we collected was telling us about these devices. By the end of the summer, all of us had chosen a part of the fabrication process of these solar cells to conduct our own experiment on, and present our findings as a research poster.

The part of the process I chose to focus on was the ligand exchange treatment for the PbS absorption layer of the cells. The goal of my experiment was to try out a different chemical for the ligand exchange treatment in the cells than the one we had been using for most of the summer.

The poster I have shared below details the role that the ligand exchange treatment plays in the function of the solar cell, the purpose of conducting this experiment, and the results of the experiment. I presented this poster at the Mount Holyoke College SPS Summer Research Poster Session in October 2017.

For more information on the Arango Lab:

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